read message in windows application

SerialPort port = new SerialPort();
if (sp.IsOpen)
{
    sp.Close();
}

sp.PortName = "COM14";
sp.BaudRate = 9600;
sp.Parity = Parity.None;
sp.DataBits = 8;
sp.StopBits = StopBits.One;
sp.Handshake = Handshake.XOnXOff;
sp.DtrEnable = true;
sp.RtsEnable = true;


sp.Open();

if (!sp.IsOpen)
{
    MessageBox.Show("Serial port is not opened");
    return;
}